Investigation of superconducting and non-superconducting phases of Na₀Ì£₃CoO₂·1.3H₂0

Other Contributors:Massachusetts Institute of Technology. Dept. of Physics.

Advisor:Young S. Lee.

Department:Massachusetts Institute of Technology. Dept. of Physics.

Publisher:Massachusetts Institute of Technology

Date Issued:2004

Abstract:

The discovery of unconventional superconductivity in hydrated Na₀Ì£₃CoO₂·1.3H₂0 has lead to active research work on the material over the last year due to its similarities and possible insight into the high-T[sub]c copper oxide superconductors as well as the possibility of other rich physical phenomenon. In this thesis, experimental evidence is presented illustrating the existence and properties of a previously unknown non-superconducting phase of Na₀Ì£₃CoO₂·1.3H₂0. This evidence includes magnetic susceptibility and x-ray scattering studies which suggest that the appearance of this phase is not due to underhydration and that a superconducting state can be restored via annealing at temperatures above roughly 340 K. Furthermore, synchrotron x-ray scattering of the non-superconductor reveals a 3-c modulation which is clearly absent in the superconducting phase of the material as well as unexpected temperature dependence behavior in the associated Bragg peaks.